<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		.box{
			width:100px;
			height:100px;
			background-color:red;
			/*脱离文档流，相当于不存在*/
			position: absolute;
		}
		.box2{
			width:200px;
			height:100px;
			background-color:blue;
		}
	</style>
</head>
<body>

		<div class="box"></div>
		<div class="box2"></div>

</body>
</html>